Raygrantite is an extremely rare lead-zinc sulfate-silicate mineral known almost exclusively from its type locality in California. It typically occurs as small, tabular, colorless to white transparent crystals associated with other oxidized lead species.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Raygrantite

Hardness: ~3
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this raygrantite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch raygrantite with a known reference. Raygrantite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals.

Often confused with

Raygrantite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Cerussite

Mohs 3-3.5

How to tell apart: Luster reads vitreous on Raygrantite and adamantine, tending toward vitreous, resinous on Cerussite.

How to tell apart: Luster reads vitreous on Raygrantite and adamantine, resinous to vitreous on Anglesite.

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Often found alongside raygrantite

Minerals reported to co-occur with raygrantite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Pb₁₀Zn(SO₄)₆(SiO₄)₂(OH)₂
Mohs hardness: ~3
Density: 6.374 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Tabular crystals
Cleavage: Good on {120}
Rarity: Rare
Uses: Collector
Host rock: By alteration of sulfides in a hydrothermal quartz-galena-pyrite-chalcopyrite vein

Where rockhounds find raygrantite

Classic worldwide localities

Evening Star mine (previously called Old Queen Group or Silver Queen mine), Big Horn Mountains, Maricopa County, Arizona, USA

Field-hunting tip

Where it forms: By alteration of sulfides in a hydrothermal quartz-galena-pyrite-chalcopyrite vein. If you start seeing galena, anglesite, cerussite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify raygrantite?+

Mohs hardness is ~3. Luster: vitreous. The streak is white. Common colors include colorless.

Where is raygrantite found?+

Notable localities include Evening Star mine (previously called Old Queen Group or Silver Queen mine), Big Horn Mountains, Maricopa County, Arizona, USA.

Is raygrantite safe to handle?+

Raygrantite contains lead. Contains lead. Wash hands thoroughly after handling and avoid inhaling dust or powder.

What rocks look like raygrantite?+

Raygrantite is most often confused with Cerussite, Anglesite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with raygrantite?+

Raygrantite commonly co-occurs with Galena, Anglesite, Cerussite, Lanarkite, Leadhillite, Mattheddleite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does raygrantite form in?+

Where it forms: By alteration of sulfides in a hydrothermal quartz-galena-pyrite-chalcopyrite vein. Working float back to the host body is the standard way to chase a fresh occurrence.

What is raygrantite used for?+

Raygrantite is used in collector.

Find raygrantite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.